Absorbent articles, such as diapers for infants and adults, sanitary napkins, and adult incontinence garments, are well known within the art and used widely. Most such products today are used on a single-use basis. The single-use basis of such disposable products have led to the development of a wide assortment of different products to meet specific requirements, e.g. in infant and toddler care, as well as in adults suffering from incontinence. The main purpose of such absorbent articles is normally to absorb, retain and isolate body waste products, such as urine, feces or blood.
Absorbent articles which respond to an event, such as urination or defecation, related to the absorption of a fluid into or onto the product, are also well known within the art. This response is normally a signal after the event has occurred and is based on a measure of, for example, wetness, temperature or mass change. The signal may be an optical signal, including visual signals, an audio signal, a chemical signal or an electrical signal. The signal can give the wearer himself/herself or nursing aid feedback information that an event has occurred, which would ease clean-up procedures for both parties.
Many of these articles incorporate sensors, the latter of which may function in a wide variety of ways. For example:
WO 2004/021944 discloses a disposable sensoring absorbent structure for detecting wetness, comprising at least one absorbent layer and at least one sensing device comprising a magnetoelastic film. The absorbent structure enables means and methods for monitoring the status, e.g. wetness, at least one biological analyte and/or at least one chemical analyte, in an absorbent article.
WO 00/16081 discloses a system comprising a resonant circuit which is at least partly formed from a moisture sensitive material, the electrical resistance of which increases when the material comes into contact with moisture. The system also comprises at least one electronic sensor for detecting the presence of moisture, and at least one reading device for obtaining information from the sensor about the presence of moisture.
U.S. Pat. No. 5,808,554 discloses a garment diaper detector for detecting wetness conditions in diapers or undergarments comprising a capacitive sensor located within a housing and affixed to the exterior surface of the garment being monitored. The sensor is comprised of two substantially solid, coplanar conductor plates affixed to a common substrate and has a very high dynamic range. When the inside of the garment becomes wet, the capacitance between the spaced conductors rises above a predetermined value whereupon the detector provides an output to a transmitter or an alarm. One particular group of direct users or wearers of such absorbent articles would include psychiatric patients suffering from dementia or other psychological illnesses, who additionally suffer from varying degrees of incontinence. These persons may not feel any inhibitions about excretory functions and may remove their incontinence garments either before urination/defecation or immediately after, thereby contaminating themselves and/or their surroundings, resulting in unpleasant clean-up activities for the nursing staff.
In such a case, the presence of an “unfastening” sensor or detector in the incontinence garment would be contemplated to be of great utility and advantage. Such a sensor would register and raise an alarm when the incontinence article is unfastened or completely removed from the body of the wearer.
The presence of a removal sensor would also be anticipated to be of utility for normal wearers such as children or persons suffering from incontinence problems, where, for example, the accidental removal of absorbent articles during sleep would lead to an alarm signal. None of the above cited art describes absorbent articles comprising a sensor for detection of unfastening or complete removal from the body of the wearer.